Cherie makes a grab for power

If this sneak picture, taken as the couple wave to the ranks of press photographers outside No 10, is anything to go by, it's Cherie Blair and not Gordon Brown who has a firm grip on the Prime Minister.

As the pack outside shout "Over here, Tony" Mrs Blair playfully attempts to distract her husband with a cheeky grab for his bottom.

Of course it's not genuine, but posed by lookalikes in the latest advert from Schweppes's "Sch ... you know who" campaign. In small print is the disclaimer: "You know it's not them."

After the success of the drinks company's campaign featuring "Camilla Parker Bowles" being dressed for her wedding by fashion designer "Karl Lagerfeld" and "Lord Archer" being visited in jail by "Baroness Thatcher", Schweppes thought it would go one better. Andrew Cocker, communications director of parent company Coca-Cola, said: "It's a great image which we think most people will find amusing and slightly cheeky."

Or as Schweppes puts it: "Each ad fixes on a common topical public perception about a character and, to the discerning, subtly suggests something more thought provoking." Downing Street refused to comment.